This solution will take you through step by step on how to integrate your mobile account with 3CX. If a mobile account has not already been set up then refer to How Do I Set Up A Mobile Account?

Step 1:
Set up the 3CX extension
Step 2: On the Sip Trunk Plus portal, select the desired mobile account you wish to integrate and right-click to ‘Add IP PBX Integration’.
Step 3: Select ‘3CX’ from the drop down menu and press 'next'. You should then see the following window:

Step 4: Enter the ‘Extension’, ‘Password’, ‘Proxy’ and 'Authorization IP' of the 3CX device you will have set up prior (ensure the ‘Extension’ > ‘Options’ has ‘Disallow use of external outside the LAN’ is unchecked/unticked). 
Please note: 
 The 'Proxy' field should be presented as {domain name \ ip address}:{port} , where {port} is an optional parameter, and must not be preceded by http, https or www.
b) The 'Authorization IP' field should be presented as a common IP address. It's used in the SIP Trunk Plus portal only to identify the gateway for the integrated SIM.

Please also refer to the following solution Setting Up Firewalls & Gateway Devices when setting up the above integration, in particular: -167 and,, and